Conventionally, memory systems including a nonvolatile memory and a volatile memory are known. The nonvolatile memory functions as storage. The volatile memory is used as a buffer of data to be written onto the nonvolatile memory, or as an area in which various kinds of management data are stored.
Such a memory system may include a capacitor. Upon detecting stop of a power supply, the memory system writes data stored in the volatile memory to the nonvolatile memory, using electric power accumulated in the capacitor. Thereby, data is saved from the volatile memory to the nonvolatile memory. This prevents loss of the data from the memory system. Such a function is known as a power loss protection (PLP) function.